France: Adverse weather forecast across much of the country through at least Sept. 27

Severe weather is forecast across much of France through at least Sept. 27. Heavy rainfall, strong winds, and isolated thunderstorms are expected across most of mainland France, with the exception of some far northern and far southern regions. The heaviest rainfall is likely in eastern regions, with rainfall accumulations up to 10 cm (4 inches) possible. Heavy downpours may trigger flooding in low-lying areas and strong winds could cause property damage and power outages.

As of Sept. 26, Meteo France has issued orange rain-flood warnings (the middle-level on a three-tier scale) for Ain, Haute-Savoie, and Jura departments in eastern France Sept. 26. Yellow rain-flood warnings are in place across north-central and western regions and yellow strong wind warnings across central and eastern regions Sept. 25. Yellow rain-flood, strong wind, and thunderstorm warnings are in place across much of mainland France Sept. 26. Officials could update and extend the coverage of weather alerts over the coming days.

Sustained heavy rainfall could trigger flooding in low-lying communities near rivers, streams, and creeks. Urban flooding is also possible in developed areas with easily overwhelmed or a lack of stormwater drainage systems. Sites located downstream from large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall. Landslides are possible in hilly or mountainous areas, especially where heavy rain has saturated the soil.

Authorities could issue mandatory evacuation orders for flood-prone communities over the coming days. Where significant flooding, landslides, or strong winds impact utility networks, disruptions to electricity and telecommunications services are possible.

Floodwaters and debris flows may render some bridges or roadways impassable, impacting overland travel in and around affected areas. Ponding on road surfaces could cause hazardous driving conditions on regional highways. Authorities could temporarily close some low-lying routes that become inundated by floodwaters. Severe weather could also trigger flight delays and cancellations at airports across the affected region.

Localized business disruptions may occur in low-lying areas; some businesses might not operate at full capacity because of flood damage to facilities and some employees' inability to reach work sites.